The extensive care needs of older adults with Alzheimer?s disease and related dementias (ADRD) typically place great demands on family members to provide informal care1, but we have little evidence of whether lack of family support may correlate with differences in health outcomes and health care utilization patterns.2 Unmet needs for informal care have been shown to lead to negative health impacts,3-5 and it is known that increasing rates of childlessness, aging single, and other transformations in family structure are yielding a growing number of older adults who have ADRD with few family available.6 In the absence of strong family support, informal caregiving arrangements may be fragile (for example, if an elderly spouse who is primary caregiver falls ill or dies).7 While some older adults receive care from friends, neighbors, or other unrelated persons,8-10 a large but unknown number are ?incapacitated and alone.?11-13 Conducting research on older adults with ADRD who are without family is challenging: the demands of research procedures and protocols for the protection of human subjects make them difficult to access in the absence of a proxy who can speak for them.10,14 As the U.S. population ages and the burden of dementia grows, there is a critical need to build an evidence base that can inform the design of interventions to support informal caregiving and improve care for older adults with ADRD who lack family support, whom efforts targeting family caregivers may miss. Our long-term goal is to produce empirically grounded knowledge about the lives and social relations of older adults with dementia, and how these shape health. This knowledge will provide a foundation for improving care for the growing population of older adults with ADRD. Our overall objective in this project is to determine whether there are systematic differences in health outcomes or patterns of health care utilization among older adults with ADRD that correlate with differing strength of family support. To accomplish this objective we will examine data from the Adult Changes in Thought (ACT) study -- an ongoing longitudinal cohort study of incident dementia among older adults who receive care within a single health maintenance organization in the Seattle area -- in combination with data from participants? health records following the diagnosis of dementia.15-17 Although no generally agreed-upon measure of social support exists, knowledge about the different types of relationships composing networks provides insight into the kind of support to which older adults have access.7 We conceptualize family support as multidimensional, encompassing who the family members are (e.g., spouse, child, sibling or other relationship category); how many family members there are; how geographically close family members are; and how emotionally close and supportive the relationships are. Although the ACT study was not designed to evaluate family networks or caregiving, the study data collected prospectively over many years offers a rich source of information about each of these domains: participants? marital situation, how many children or siblings they have, who they live with, and their responses to a social support survey that includes questions about informational, emotional, and instrumental support. We will leverage each of these data elements to measure the strength of family support for study participants, and link these to participants? health records to examine whether differences in strength of family support correlate with health outcomes or health utilization patterns. Our interpretation of these findings will be enriched by qualitative analysis of chart notes for a subset of participants. Our central hypothesis is that older adults with ADRD who lack strong family support will exhibit worse health outcomes and different patterns of health service utilization, as compared to those with strong family support. The broad long-term objective of this research is to document possible health correlates of lack of family support for adults with ADRD, to inform the design of interventions to improve care and support for informal caregiving for this population. Our core research team has expertise in anthropology, gerontological social work, dementia research and relevant aspects of clinical care including geriatrics, palliative care, internal medicine and home health. Members of our team share long histories of successful collaboration on mixed- methods health research and experience with the ACT study data.